HM Queen Sofia of Spain is sister of HM King Konstantinos II of the Hellenes and they are first cousins of HRH Prince Ernst August of Hannover.
HM Queen Margrethe II of Denmark is sister of HM Queen Anne Marie of the Hellenes. They are first cousins of HM King Carl XVI Gustaf of Sweden.
HM King Harald V of Norway is first cousin of HM King Albert II of the Belgians and HRH Grand-duchess Joséphine-Charlotte of Luxembourg.
HM Queen Anna of Romania is first cousin of HRH Grand-duke Jean I of Luxembourg, HIRH Archduke Otto of Austria and HRH Duke Carlos Hugo of Bourbon-Parma, and they are cousins of HM King Simeon II of the Bulgarians.
HRH Crown Prince Vittorio Emanuel of Italy is first cousin of HM King Albert II of the Belgians and HRH Grand-duchess Joséphine-Charlotte of Luxembourg.
HRH Crown Prince Aleksandr of Serbia is first cousin of TM King Konstantinos II of the Hellenes and Queen Sofia of Spain, HRH Crown Prince Vittorio Emanuel of Italy and HRH Prince Nikola of Montenegro.
HSH Prince Albert of Saxe-Coburg-Gotha married his first cousin HM Queen Victoria I of Great-Britain; their first cousin HSH Prince Ferdinand of Saxe-Coburg-Gotha married HM Queen Maria II of Portugal (he took the style of HM King Fernando II).
HSH Prince Leopold of Saxe-Coburg-Gotha, uncle of HRH Prince Albert and HM King Fernando II, was elected King of Belgium (HM King Léopold I of the Belgians); HSH Prince Ferdinand of Saxe-Coburg-Gotha, nephew of HM King Léopold I was elected King of Bulgaria (HM King Ferdinand I of the Bulgarians).
The descendents of these four Couburgs (Albert, Fernando II, Léopold I and Ferdinand I) are the Heads of the most Royal, Imperial and Grand-ducal Houses of Europe, including the Queen of Great-Britain and Denmark, the Kings of Spain, Sweden, Norway, Belgium, Romania, Greece and Bulgaria, the Grand-duke of Luxembourg, the Crown Princes of Italy and Serbia and the Heads of the Royal House of Portugal and the Imperial House of Germany.